Tumor Markers in the Diagnosis, Monitoring and Therapy of Pancreatic Cancer: State of the Art

Insights on Proteomics-Driven Body Fluid-Based Biomarkers of Cervical Cancer

Cervical cancer is one of the top malignancies in women around the globe, which still holds its place despite being preventable at early stages. Gynecological conditions, even maladies like cervical cancer, still experience scrutiny from society owing to prevalent taboo and invasive screening methods, especially in developing economies. Additionally, current diagnoses lack specificity and sensitivity, which prolong diagnosis until it is too late. Advances in omics-based technologies aid in discovering differential multi-omics profiles between healthy individuals and cancer patients, which could be utilized for the discovery of body fluid-based biomarkers. Body fluids are a promising potential alternative for early disease detection and counteracting the problems of invasiveness while also serving as a pool of potential biomarkers. In this review, we will provide details of the body fluids-based biomarkers that have been reported in cervical cancer. Here, we have presented our perspective on proteomics for global biomarker discovery by addressing several pertinent problems, including the challenges that are confronted in cervical cancer. Further, we also used bioinformatic methods to undertake a meta-analysis of significantly up-regulated biomolecular profiles in CVF from cervical cancer patients. Our analysis deciphered alterations in the biological pathways in CVF such as immune response, glycolytic processes, regulation of cell death, regulation of structural size, protein polymerization disease, and other pathways that can cumulatively contribute to cervical cancer malignancy. We believe, more extensive research on such biomarkers, will speed up the road to early identification and prevention of cervical cancer in the near future.

Cholestasis is the Main Determinant of Abnormal CA 19–9 Levels in Patients with Liver Cirrhosis

Background/Aims

Altered CA19–9 levels are commonly found in patients with liver cirrhosis though a clear explanation for this finding has not yet been given. The aim of this study was to investigate whether CA19–9 levels might be related to alterations in biochemical parameters and/or to functional impairment in cirrhotic patients with and without hepatocellular carcinoma. Methods: We studied 126 patients with liver cirrhosis, 60 of whom also had hepatocellular carcinoma. CA19–9 values were related to clinical, biochemical and functional parameters. In half of the patients CA19–9 levels were related to the monoethylglycinexylidide test, which is a dynamic liver function test.

Results

In more than half the cases CA19–9 values were above the upper limit. Liver function worsening as assessed by Child-Pugh's score and monoethylglycinexylidide test did not seem to influence the alteration of the marker. By contrast, in univariate analysis CA19–9 correlated with aminotransferases, γ-glutamyltransferase and alkaline phosphatase. Multivariate analysis showed that besides alkaline phosphatase also the presence of hepatocellular carcinoma might influence the alteration of CA19–9, although the marker was of no use for the diagnosis of liver cancer in patients with altered though not diagnostic α-fetoprotein levels.

Conclusions

In our study we confirmed the correlation of CA19–9 levels with cholestasis and cytolysis parameters. Moreover, we found no association between CA19–9 levels and impaired liver function as assessed by means of the Child-Pugh's score and the monoethylglycinexylidide test, which is cholestasis-independent and explores liver metabolic and clearance activities. The cholestatic picture that characterizes liver cirrhosis might enhance the expression and passage of the marker from the bile to the blood. The addition of CA19–9 assessment is not useful for the diagnosis of hepatocellular carcinoma in patients with non-diagnostic levels of α-fetoprotein. Caution should therefore be used when evaluating CA19–9 in cirrhotic patients with cholestasis, since false positive results may occur.

Elevated serum CA 19-9 levels in patients with pulmonary nontuberculous mycobacterial disease

Increased serum CA 19-9 levels in patients with nonmalignant diseases have been investigated in previous reports. This study evaluates the clinical significance of serum CA 19-9 elevation in pulmonary nontuberculous mycobacterial disease and pulmonary tuberculosis. The median CA 19-9 level was higher in patients with pulmonary nontuberculous mycobacterial disease than in patients with pulmonary tuberculosis (pulmonary nontuberculous mycobacterial disease: 13.80, tuberculosis: 5.85, p < 0.001). A multivariate logistic regression analysis performed in this study showed that Mycobacterium abscessus (OR 9.97, 95% CI: 1.58, 62.80; p = 0.014) and active phase of pulmonary nontuberculous mycobacterial disease (OR 12.18, 95% CI: 1.07, 138.36, p = 0.044) were found to be risk factors for serum CA 19-9 elevation in pulmonary nontuberculous mycobacterial disease. The serum CA 19-9 levels showed a tendency to decrease during successful treatment of pulmonary nontuberculous mycobacterial disease but not in pulmonary tuberculosis. These findings suggest that CA 19-9 may be a useful marker for monitoring therapeutic responses in pulmonary nontuberculous mycobacterial disease, although it is not pulmonary nontuberculous mycobacterial disease-specific marker.

Extremely increased serum carbohydrate antigen 19-9 levels caused by new or resistant infections to previous antibiotics in chronic lung diseases

In this paper, we describe 72-year-old female patient without evidence of malignant disease presented with significantly elevated serum carbohydrate antigen (CA) 19-9 levels by respiratory infections. She was diagnosed with respiratory infections due to Mycobacterium avium complex and Pseudomonas aeruginosa. The serum CA 19-9 levels remarkably increased (1,453-5,300 U/mL; reference range, <37 U/mL) by respiratory infection and abruptly decreased (357-534 U/mL) whenever infection was controlled by specific treatments. This case suggests that serum CA 19-9 levels may be used as a diagnostic marker to indicate new or resistant infections to previous antibiotics in chronic lung diseases without significant changes in chest X-ray findings.

Plasma concentrations of angiogenetic factors and angiogenetic inhibitors in patients with ductal pancreatic neoplasms. A pilot study

BACKGROUND

The aim of the study was to evaluate the circulating concentrations of vascular endothelial growth factor (VEGF), vascular endothelial growth factor receptor-2 (VEGFR-2), vascular endothelial growth factor-D (VEGF-D) and endostatin in patients with intraductal papillary mucinous neoplasm (IPMN), and in those with ductal adenocarcinomas.

METHODS

Sixty patients (32 males, 28 females, mean age 69.3±11.3 years) were enrolled: 31 (51.7%) had IPMNs and 29 (48.3%) had histologically confirmed pancreatic adenocarcinomas. Thirty blood donors were also studied as controls. In all study subjects, the concentrations of VEGF, VEGF-D, VEGFR-2, and endostatin were determined using enzyme-linked immunosorbent assays.

RESULTS

Serum concentrations of VEGF, VEGF-D, and VEGFR-2 were significantly higher in patients with pancreatic ductal adenocarcinoma and those with IPMNs compared with healthy subjects, while endostatin was significantly higher only in patients with pancreatic ductal adenocarcinoma compared with healthy subjects. Within the group of patients, VEGFR-2 was significantly higher in patients with ductal adenocarcinoma compared to those with IPMNs. The sensitivity and the specificity of VEGFR-2 in differentiating patients with ductal adenocarcinomas from those with IPMN at a cut-off range of 4003-4034 pg/mL was 86.2% and 54.8%, respectively.

CONCLUSIONS

IPMNs have serum VEGFR-2 concentrations different from those in patients with ductal adenocarcinomas. However, serum VEGFR-2 cannot be routinely utilized to differentiate IPMNs from pancreatic ductal adenocarcinomas.

Transcriptional recapitulation and subversion of embryonic colon development by mouse colon tumor models and human colon cancer

Colon tumors from four independent mouse models and 100 human colorectal cancers all exhibited striking recapitulation of embryonic colon gene expression from embryonic days 13.5-18.5.

Background

The expression of carcino-embryonic antigen by colorectal cancer is an example of oncogenic activation of embryonic gene expression. Hypothesizing that oncogenesis-recapitulating-ontogenesis may represent a broad programmatic commitment, we compared gene expression patterns of human colorectal cancers (CRCs) and mouse colon tumor models to those of mouse colon development embryonic days 13.5-18.5.

Results

We report here that 39 colon tumors from four independent mouse models and 100 human CRCs encompassing all clinical stages shared a striking recapitulation of embryonic colon gene expression. Compared to normal adult colon, all mouse and human tumors over-expressed a large cluster of genes highly enriched for functional association to the control of cell cycle progression, proliferation, and migration, including those encoding MYC, AKT2, PLK1 and SPARC. Mouse tumors positive for nuclear β-catenin shifted the shared embryonic pattern to that of early development. Human and mouse tumors differed from normal embryonic colon by their loss of expression modules enriched for tumor suppressors (EDNRB, HSPE, KIT and LSP1). Human CRC adenocarcinomas lost an additional suppressor module (IGFBP4, MAP4K1, PDGFRA, STAB1 and WNT4). Many human tumor samples also gained expression of a coordinately regulated module associated with advanced malignancy (ABCC1, FOXO3A, LIF, PIK3R1, PRNP, TNC, TIMP3 and VEGF).

Conclusion

Cross-species, developmental, and multi-model gene expression patterning comparisons provide an integrated and versatile framework for definition of transcriptional programs associated with oncogenesis. This approach also provides a general method for identifying pattern-specific biomarkers and therapeutic targets. This delineation and categorization of developmental and non-developmental activator and suppressor gene modules can thus facilitate the formulation of sophisticated hypotheses to evaluate potential synergistic effects of targeting within- and between-modules for next-generation combinatorial therapeutics and improved mouse models.

Serum levels of CA19-9 in patients with nonmalignant respiratory diseases

CA19-9 is a specific tumor marker in patients with gastrointestinal cancer; however, some patients with respiratory disease can have elevated serum levels of CA19-9 as well. In this study we evaluated serum CA19-9 levels of patients with nonmalignant respiratory diseases. We also estimated the prognostic significance of elevated serum levels of CA19-9 in patients with interstitial lung diseases. The study included 554 patients who had been diagnosed at our hospital during the period of 1984-2005. Serum CA19-9 levels in these patients were measured with a commercially available kit. Elevated levels (>37 U/mL) of CA19-9 were observed in 30.7% of patients with lung cancer. Furthermore, 38.9% of patients with idiopathic interstitial pneumonia (IIP), collagen disease-associated pulmonary fibrosis (CDPF), diffuse panbronchiolitis (DPB), and bronchiectasis had elevated serum CA19-9 levels. Survival rates were significantly lower in patients with interstitial lung diseases (IIP and CDPF) and elevated serum CA19-9 levels than in those with levels in the normal range (P=0.0065). Serum CA19-9 was elevated in some patients with nonmalignant diffuse lung diseases. Therefore, clinicians should pay attention to the evidence that increased serum CA19-9 levels can be found in nonmalignant respiratory disease patients. In patients with IIP and CDPF, elevated serum CA19-9 levels may be related to poor prognosis.

Screening of glycosylation patterns in serum using natural glycoprotein microarrays and multi-lectin fluorescence detection

Protein glycosylation has been implicated in key biological processes including immunological recognition, cellular adhesion, protein folding, and signaling as well as disease progression. Although several methods are available to assess glycosylation of protein structures, none of them is able to screen complex biological samples at a global as well as an individual scale. A novel strategy presented here uses an all-liquid phase enrichment and prefractionation methodology coupled to glycoprotein microarray technology using a multiple lectin-based, biotin-streptavidin detection scheme. Selective detection of glycan structures was made possible by employing multiple lectins to screen glycoprotein standards as well as serum samples from normal subjects or patients with chronic pancreatitis or pancreatic cancer. Interestingly, in some instances, a greater degree of glycosylation was seen in proteins that were underexpressed based on the reversed-phase chromatogram alone. Studies with standard proteins established the limits of detection to be in the 2.5-5-fmol range. Studies on serum samples showed differences in glycosylation patterns, particularly with respect to sialylation, mannosylation, and fucosylation, in normal, pancreatitis, and cancer sera. By coupling glycoprotein enrichment and fractionation with a microarray platform, we have shown that naturally occurring glycoproteins from human serum can be screened and characterized for different glycan structures, thereby allowing one to do comparative studies that monitor individual glycosylation changes within a glycoproteome representing different biological states. This approach may be useful to identify potential biomarkers in cancer.

Serum protein profiles of patients with pancreatic cancer and chronic pancreatitis: searching for a diagnostic protein pattern

In this study, 13 sera from patients with pancreatic cancer, 9 from chronic pancreatitis and 10 from healthy subjects were analyzed by matrix-assisted laser desorption/ionization (MALDI) mass spectrometry. The MALDI mass spectra revealed the presence of several low molecular weight peptides, among which some were detected only in the sera from both pathological conditions. On the other hand many peptides were observed only in control sera, and were absent in the sera from the two diseases. Therefore, MALDI analysis of the low molecular weight fraction (<10 000 Da) of sera from patients with pancreatic diseases enabled us to identify the presence of some disease-related signals and also some signals characteristic of normal subjects.

ME-PCR for the identification of mutated K-ras in serum and bile of pancreatic cancer patients: an unsatisfactory technique for clinical applications

Our aim was to assess the clinical reliability of mutated K-ras detection in serum or bile for the diagnosis of pancreatic cancer using ME-PCR. DNA was extracted from 1 ml serum obtained from 29 patients with pancreatic cancer and 12 control subjects. ME-PCR was optimized using a mixture of normal DNA added with different amounts of mutated DNA. The analysis of sera obtained from the 29 patients and of bile obtained from 11 pancreatic cancer patients demonstrated the presence of mutated K-ras in two (6.9%) and four cases (36%). By contrast K-ras was not amplifiable in any of the 12 serum samples obtained from healthy controls. In conclusion the DNA obtained from pancreatic cancer patients' sera is suitable for K-ras amplification and for the identification of codon 12 point mutations. However ME-PCR alone has an unsatisfactory sensitivity for the detection of pancreatic cancer using serum DNA as starting template.

Role of tumour markers, cytogenetics

A review is presented on the role of conventional and molecular tumour markers (TM) in diagnosis and monitoring of patients with biliopancreatic malignancies. For biliopancreatic malignancy, following CEA as more historical and basic TM of gastrointestinal diseases, the mainstay marker is CA 19-9 as monosialo-ganglioside/glycolipid and sialyl derivative of lacto-N-fucopentaose II (sialyl-Lewis(a), hapten of human Lewis(a) bloodgroup determinant). It is detected in serum of healthy individuals at low concentration < 40 U/ml, with lower and often transitional elevation in benign hepatobiliary diseases and with highest levels in excretory ductal pancreatic adenocarcinoma (s = 70%-95%, sp = 72%-90%), biliary (s = 55%-79%), hepatocellular and cholangiocellular cancer (s = 22%-51%) besides gastric, colorectal and ovarian cancer and occasionally in lung, breast and uterine cancer. Physiologically elevated concentrations in healthy individuals have to be considered in all sorts of secretions (e.g. sputum, saliva, bronchial/gastric secretions, bile juice) of individuals with Lewis(a)-positive secretor status in contrast with low or lacking serum levels of CA 19-9 in patients with Lewis(a-/b-) status (7%-10% of population). In biliopancreatic malignancies, especially pancreatic cancer, CA 19-9 correlates well with clinical course of disease following surgical, chemo- or radiotherapy by a quick normalisation within 2-4 weeks after complete surgery, a transient decrease with successful palliative therapy and an often anticipated increase (lead time up to 6 months) before clinical detection in case of relapse or progressive disease. From CA 19-9 related TM tests some are detecting in addition to sialyl-Lewis(a) (sialyllacto-N-fucopentaose II) also the non-fucosylated precursor sialyl-Lewis(c) (sialyllacto-N-tetraose: CA 50, CA 242, Span-1) solely detected by the DUPAN-2 test and independent of the Lewis(a) secretor status. Some other markers comprise in addition to sialyl-Lewis(a) partially the non-sialylated Lewis(a) antigen (CA 195, CAM 43, CA 494) or are less related (CAM 17.1). The initial phase of screening and early detection is hoped to be better assessed by using molecular markers detecting gene mutations (p53, K-ras), growth factors (EGF, TGF-alpha, TGF-beta, HB-EGF, a/bFGFs, KGF) and growth factor receptor alterations (EGFr, c-erbB2/3/4). From these, K-ras mutations detected in blood, stool and bile juice of patients at risk for pancreatic cancer seem to be more promising than p53 alterations as a more later step in carcinogenesis, although they are neither yet well established nor standardised by reliable assays. In contrast growth factor and growth factor receptor alterations mainly concerning signal transducing systems seem to reflect increased tumour aggressiveness, thus shorter survival and poorer prognosis thereby contributing in the selection of patients for more aggressive therapy.

K-ras mutations in stools and tissue samples from patients with malignant and nonmalignant pancreatic diseases

Mutant-enriched PCR and reverse dot blot hybridization in microplates were applied for examining K-ras status in stools and tissue samples from patients with pancreatic tumors and chronic pancreatitis. In tissue samples, K-ras mutations were found in 32 of 35 cases of ductal adenocarcinoma, in 5 of 7 periampullary cancers, in 1 cystadenocarcinoma, and in 3 of 5 patients with chronic pancreatitis. In stools, mutated K-ras was seen in 10 of 25 cases of ductal adenocarcinoma, in 1 case of cystadenocarcinoma, and in 2 of 6 cases of chronic pancreatitis. These data indicate that the K-ras status of stool samples may help identify pancreatic carcinoma and persons at risk for cancer development; however, it does not allow discrimination of malignant from nonmalignant diseases.

Portal but not peripheral serum levels of interleukin 6 could interfere with glucose metabolism in patients with pancreatic cancer

Interleukin 6 (IL-6), an autocrine growth factor for many tumors, seems to favour tumor spread to the liver. Our aims were first to evaluate the pattern of portal and systemic IL-6 levels in patients with pancreatic cancer (PC, n = 18) and chronic pancreatitis (CP, n = 22) compared with controls (CS, n = 20); and second, to ascertain whether there was any relation between IL-6 levels and tumor spread or PC-associated Diabetes mellitus. For all subjects, a fasting serum sample was obtained from a cubital vein; a portal serum sample was obtained from nine PC and three CP patients. In cubital and portal sera we measured IL-6, interleukin 1 beta (IL-1b), CA 19-9, c-reactive protein (CRP) and amylase. Systemic IL-6 levels were significantly higher in PC patients than in CS. In PC, portal IL-6 levels were significantly higher than the corresponding systemic values. The same pattern was found in the three CP patients, whereas IL-1b, CA 19-9, CRP and amylase portal levels were the same as systemic values. No correlation was found between PC stage and systemic or portal IL-6 levels. Portal IL-6 levels were correlated with the corresponding fasting serum glucose values. A significant correlation was found between IL-6 values and CRP, ALT, total bilirubin, GGT and creatinine, but not amylase.

IN CONCLUSION

(1) Portal IL-6, which is partly of pancreatic origin, is first metabolised in the liver; (2) Systemic IL-6 reflects hepatic and renal functions rather than local conditions in the pancreas; (3) IL-6 does not appear to influence PC spread; (4) IL-6, which is released in large amounts by the inflamed pancreas, may contribute to determining diabetes, thus interfering with the signal transducing pathways involved in glucose metabolism in liver cells.